Alright Billy, there are a myriad of ways to accomplish what you are asking.
This is the commerce section of the SWC forum:
Here you can find other players offering a variety of items, vehicles, ships, stations, facilities and services of all types.
Next you have IRC. You can download most any type of IRC client like mIRC (most common), Mibbit and Trillian. It's a large chat area with "channels" (rooms) where people trade, talk and conduct faction business. You'll probably find your way there for a bunch of reasons. Here is a guide to help you get started with that: http://www.swcombine.com/guide/index.php?page=5
Then you have Centrepoint Marketplace. This is an excellent source to use when buying/selling items. Find it here: http://market.centrepointstation.com/index.php
Togan Jano, who is on leave right now, will be able to set you up an account when he gets back.
And finally you can contact factions directly to purchase their products or hire them for the services they offer. You can find faction information by doing the following:
Right hand menu --> click the "wrench" symbol --> under the In Character section choose "Factions" --> scroll the different types of factions and choose the one you'd like to see --> after clicking on a faction hover over the name of the faction and you'll see that you can click it. this will bring you to the faction's holosite. they are required to have a page with services listed.
Now, all this being said if you are just starting you, which is sounds like you are, you'll have to be patient and earn some credits first before you can do things. Looking around at the places above you'll find that some things are very expensive, especially for a new player. But keep your head about you, work hard and you'll reach your goals in no time.
For starting a town I'd like you to take a look here first just to get you started and then ask any questions you have:
Laying a city foundation: http://www.swcombine.com/rules/?Cities
Build a facility: http://www.swcombine.com/rules/?Facility_Construction
Billy, first you need the sufficient credits to buy the item that you want (it varies from seller to seller, but usually they are the same). Then you need to contact the seller to request a purchase, then they will send you the item(s) that you have purchased and you would send the credits.
If you need a ship, I would recommend joining a faction, as they usually provide you with one.